Oil burner



Sept. 8, 1959 c. c. BLACKMAN 2,903,051

on. BURNER Filed Dec. 6, 1957 2 Sheets-Sheet 1 INVENTOR. 6,44 w/v C. 644 C'KMA/V Sept. 8, 1959 c. c. BLACKMAN OIL BURNER 2 Sheets-Sheet 2 Filed Dec. 6, 1957 BYM M,

ATTUIP/Vfki United States Patent OIL BURNER Calvin C. Blackman, Bay Village, Ohio, assignor to Lee Wilson, Cleveland, Ohio 2 Application December 6, 1957, Serial No. 101,152

12 Claims. Cl. 158-28) This invention relates to burners for fluid fuel and more particularly to an oil burner adapted to be incorporated in an elongated combustion tube of the type employed for heating annealing furnaces and the like.

while the main body of the combustion tube, which may be straight, U-shaped or O-shaped, is disposed parallel to the wall. The fuel burner for supplying the proper mixture of fuel and air to the inlet end of the combustion tube is mounted externally of the furnace and extends into the section of the combustion tube which projects through the furnace wall. The fuel is ignited adjacent the end of the burner unit, and in previous burners with which I am familiar, ignition has occurred in the inlet section of the combustion tube just ahead of the inlet elbow which connects the inlet section to the main body of the combustion tube. When gas is used as fuel, there is usually no serious localized heating at the inlet elbow section of the combustion tube, but difliculty has at times been experienced when oil is used as fuel due to localized heating developing hot spots in or near the elbow. 'Ihese hot spots are undesirable in .that they may cause localized overheating of the combustion tube and shorten the effective life thereof.

It is an object of the present invention to provide a burner for use with combustion tubes of the typereferred to above whereby undesirable hot spots adjacent the inlet elbow of the combustion tube are eliminated and which may readily be taken apart and cleaned in a short time and with minimum labor.

Other objects of my invention include the provision of an improved oil burner for combustion tubes whereby the flame from the burner is directed into the combustion tube beyond the inlet elbow section; the provision of an oil burner for combustion tubes which may readily be withdrawn from its support housing for inspection and cleaning; and the provision of an oil burner for combustion tubes which is of rugged design, which may be economically manufactured, installed and maintained, which has long service life, and which is readily adapted for incorporation in existing combustion tubes.

The above and other objects of my invention will ap- .pear from the following description of one embodiment thereof, reference being had to the accompanying drawings in which:

Figure 1 is a detached perspective view, partly in cross section, illustrating an O-type combustion tube particularly designed for heating bell type annealing furnaces or the like and having my improved burner mounted at its inlet end;

Figure2 is an enlarged horizontal cross sectional view taken su s a a y n line 2:20 Figur Figure 3 is a vertical cross sectional view of the burner illustrated in Figures 1 and 2, taken substantially on line 33 of Figures 2 and 4; and

Figure 4 is a vertical cross sectional view through the burner housing, taken substantially on line 4-4 of Figure 3.

Referring to Figure l, the combustion tube C has an inlet section 1 extending at right angles through and supported by the furnace Wall 2. The main heating portion of the tube C is indicated at 3 and is generally O-shaped. The outlet section 4 extends through the furnace wall 2 above and parallel to the inlet section 1. An inlet elbow 5 connects the inlet section 1 to the main heating section 3, and in like manner an outlet elbow 6 connects the main heating section 3 to the outlet section 4. During operation, fuel and air are supplied to the combustion tube C by the burner B which is mounted on the outer end of inlet section 1 and, upon ignition of the fuel, flame and products of the combustion pass through the main heating section 3 of the combustion tube and out through the outlet section 4.

Referring to Figures 2, 3 and 4, the burner B includes a main housing 7 which is generally cylindrical in form and is provided with attaching flanges 8 and 9 at its inner end. Mounting screws 10 and 11 are welded to the inlet section 1 of the combustion tube C at its outer end and are disposed to extend through holes in flanges 8 and 9 as best seen in Figure 2. A gasket 12 seals the joint between the housing 7 and the end of inlet section 1 of the combustion tube, and the nuts 13 and 14 securely clamp the entire burner assembly to the inlet end of the combustion tube.

The main burner housing 7 has a cylindrical bore 15 extending inwardly from its outer end, and a secondary air chamber 16 extends inwardly from its opposite or inner end. The cylindrical bore 15 and the secondary air chamber 16 are co-axially arranged and join each other intermediate the ends of the housing 7 at the shoulder 17. A primary air inlet 18 in the form of a threaded hole extends through the wall of main housing 7 into the cylindrical bore 15. Primary air is supplied through a suitable pipe (not shown) connected to the inlet opening 18. A secondary air inlet opening 19', also in the form of a threaded hole, extends through the wall of the main housing 7 into the secondary air chamber 16, and it will be understood that secondary air may be supplied through a suitable pipe or conduit conuected to the inlet 19.

A support member, generally indicated at 2ft, is removably positioned in the cylindrical bore 15. This sup port member 20 somewhat resembles a plunger or piston in its general form and includes axially spaced outer and inner end discs 21 and 22 respectively. The outer peripheries of these end discs 21 and 22 have a sliding fit in the cylindrical bore 15 and are grooved to receive sealing means such as the resilient O-rings 23.

End discs 21 and 22 are connected together to form an integral unit by tubular strut-like members 24 and 25. The upper one, 24, of these struts is generally oval in cross section as seen in Figure 4, while the lower strut 25 is of circular cross section. The inner end disc 22 has a central opening 26 extending therethrough, and an integral tubular extension 22' projects inwardly into the secondary air chamber 16. The elongated primary air tube 27 is mounted in the tubular extension 22. and is thus supported by the inner end disc 22 in concentric centered position relative to the secondary air chamber 16 and the inlet section 1 of the combustion tube C. The space between the inner and outerend discs Hand 22 of the support member 20 is connected to the primary air inlet 18 and is also connected to the interiqr of primary air tube 27 through the central opening 26 in inner end disc 22.

An oil supply tube 28 extends through a central opening in the outer end disc 21 and is detachably but securely and rigidly mounted therein by means of a suitable supporting sleeve 29. As clearly seen in Figure 3, oil tube 28 extends through the space between end discs 21 and 22 of the support member 20, projects inwardly through the central opening 26 in the inner end disc 22 and is spaced from the walls thereof, and then extends co-axially through the primary air tube 27. As the pipe or tube 28 is smaller than the inner diameter of tube 27, primary air which enters the housing 7 through the inlet 18 may move freely into and through the primary air tube 27.

The inner ends of primary air tube 27 and oil tube 28 are so disposed and shaped to form an oil spray nozzle 30 (see Figure 3) which is adapted to deliver a spray of oil carried by primary air into the tubular ignition chamber generally indicated at 31. The ignition chamber '31 includes a straight tubular portion 32, cylindrical as shown and an outer elbow portion 33. These two parts or sections of the ignition chamber are of the same diameter, larger than the outside diameter of the primary air tube 27. The inner end of cylindrical portion 32 is secured to a sleeve 34 which in turn is attached to the outer end of primary air tube 27.

As previously noted, secondary air enters the main housing 7 through the inlet 19 and may pass freely through the secondary air chamber 16 into the inlet section 1 of the combustion tube C. A slot 35 is formed in the bottom of the straight tubular portion 32 of the ignition chamber 31 in order to permit a limited quantity of secondary air to enter the ignition chamber to facilitate ignition and initial combuston. It will be understood that in some cases this slot may be omitted or may be enlarged. A strut or pin 36 extends downwardly from the sleeve 34 and serves as a support for the inner end of the burner structure.

In order to direct the air and fuel supply and the flame from burner B in such a manner that hot spots at or adjacent the inlet elbow of the combustion tube will be avoided, the outer elbow portion 33 of the ignition chamber is provided. As illustrated the elbow portion 33 is a separate member from the inner portion 32 and is secured thereto by a hinge 37 mounted on the top of cylindrical portion 32. Gravity normally holds the elbow portion 33 in the position illustrated in Figure 3 in which the outlet end 33 is co-axially disposed relative to the main heating section 3 of the combustion tube.

When oil is supplied under suitable pressure to the pipe 28, and primary and secondary combustion air are supplied through the openings 18 and 19 respectively, oil will be sprayed into the straight tubular portion 32 of the ignition chamber 31 mixed with primary air from the tube 27. In order to ignite the oil, electrical conductors 38 and 39 extend through a slot 40 in the top of ignition chamber 31 and have their ends bent and disposed to form a spark gap 41 as seen in Figure 2. The conductors 33 and 39 are supported in suitable insulators 42 and 43 which are clamped to the sleeve 34 and extend rearwardly through tubular insulators 44 and 45. These insulators extend through the strut 24 and are securely mounted in the outer end disc 21 by supporting sleeves 46. Suitable connector fittings 38' and 39' are disposed at the outer ends of the conductors 38 and 39. When connections are made to a suitable source of high tension electrical current, a spark will be produced at the gap 41 which will ignite the oil being discharged from the supply tube 28 within the ignition chamber 31.

As suflicient air for complete combustion is not supplied through the primary air tube 27, unburned fuel, along with burning fuel, is discharged through the outlet 33' of the ignition chamber elbow 33. Here additional secondary air is available to produce the elongated flame which is desirable for heating this type of combustion tube. As the flame and products of combustion are directed axially into the main heating section 3 of the combustion tube, there is no direct impingement of high velocity flame or products of combustion directly against the tube walls and no hot spots are created as may occur when the end of the ignition chamber is disposed at the inlet end of the inlet elbow 5.

As previously noted, the strut 25 which connects the lower portions of end discs 21 and 22 of the support member 20 is tubular in form. A visual sighting or peephole fixture 50, having a suitable glass or lens at its outer end, is secured at the outer end of thetubular strut 25 and may have a depending handle portion 51 for convenience. By this means, the operator can visually determine whether or not the burner is functioning properly.

If it becomes necessary to inspect the inner parts of the burner, particularly the nozzle 30 and ignition chamber '31, and to remove carbon deposits therefrom, it is only necessary to take out the anchor screw 52 (see Figure 3) which projects through the main housing 7 behind the outer face of outer end disc 21 and holds the support member 20 and parts carred thereby in operating position. With the screw 52 removed, support member 20 may be pulled out of the cylindrical bore in the main housing carrying with it the primary air tube 27, oil tube 28, electrodes 38 and 3,9, and the tubular ignition cham ber 31.

Although the outlet 33 of the elbow section 33 of the ignition chamber is disposed below the bottom of the inlet section 1 of the combustion tube, the assembly may be withdrawn axially because when the inner corner of the elbow 3'3 strikes the inner face of the elbow 5, it will swing outwardly on its hinged support 37 and thus may be pulled out through inlet section 1 without ditficulty. By this hinged arrangement, it is possible to position the outlet of the ignition chamber well around the corner of the inlet elbow 5 whereby hot spots and undesirable wall impingement are effectively eliminated.

After the burner unit is cleaned, it may readily be repositioned by sliding it into and through the main housing 7, which remains attached to the inlet section 1 at all times. When the final operating position seen in Figure 2 is reached, the screw 52 is replaced to lock the assembly in position, the resilient O-rings 23 forming an effective seal against undesirable leakage around the support member.

In the above description the burner has been referred to as an oil burner. However, it will be understood that it is also adapted for burning gaseous as well as liquid fuel, and, although the hot spot and cleaning problems are usually more severe when oil is burned, the advantages of my improved apparatus are also obtained when it is employed with gaseous fuels.

Although I have described the illustrated embodiment of my invention in considerable detail, it will be understood that variations and modifications may be made in the form and proportion of the parts without departing from the spirit of my invention. For example, when the inlet section 1 of the combustion tube C is of larger diameter, relative to the burner parts, than is illustrated herein so that the ignition chamber elbow 33 would clear the bottom wall of section 1, the hinged connection between the elbow portion 33 and the cylindrical portion 32 of the tubularignition chamber 31 may be omitted and these parts may be made as an integral unit. Accordingly, I do not wish to be limited to the exact structure and arrangement shown and described herein, but claim as my invention all embodiments thereof coming within the scope of the appended claims.

I claim:

1. A burner adapted to be supported at an end of a combustion tube for burning fuel in said tube including, a main housing having a cylindrical bore extending inwardly from one end and a secondary air chamber extending inwardly from the opposite end, said cylindrical bore and said secondary air chamber joining each other "intermediate the ends of said main housing, said main housing also having a primary air inlet opening into said cylindrical bore and a secondary air inlet opening into said secondary air chamber, a support member removably positioned in said cylindrical bore, said support member having axially spaced outer and inner end discs and connecting strut means extending between said end discs, said inner'end disc having an opening therein, a primary air tube supported by'said inner end disc and extending through said secondary air chamber, the space between fsaid inner and outer end discs being connected to the interior of-said primary air tube by said opening in said "inner end disc, said outer end disc having an aperture extending therethrough, and a fuel conducting tube extending through said aperture in said outer disc and supported 'by-said support member, said fuel tube extending inwardly through and being spaced from the wall of said opening in said inner end disc into said primary air tube, and said primary air inlet in said main housing opening into thespace between said end discs of said support member.

2'. A burner adapted to be supported at an end of a combustion tube for burning fuel in said tube including, a main housing having a cylindrical bore extending inwardly from one end and a secondary air chamber extending inwardly from the opposite end, said cylindrical bore and said secondary air chamber joining each other intermediate the ends of said main housing, said main "housing also having a primary air inlet opening into said cylindrical bore and a secondary air inlet opening into "said secondary air chamber, a support member removably positioned in said cylindrical bore, said support member havin'gaxially spaced outer and inner end discs and connecting strut means extending between said end discs, said "inner" end disc having an opening therein, a primary air tube supported by said inner end disc and extending through said secondary air chamber, the space between saidfinne'r and outer end discs being connected to the interi'or'o'f said primary air tube by said opening in said inner -.end .disc, said outer end disc having an aperture extending therethrough, a fuel conducting tube extending ,flrough said aperture in said outer disc and supported bygsaid support member, said fuel tube extending inwardly through and being spaced from the wall of said opening in said'inner end disc into said primary air tube, said 'rimary air inlet in said main housing opening into 'thesp'ace between said end discs of said support member, and a tubular ignition chamber at the outer end of said fuel conducting tube and having a curved outer end portion adapted to discharge fuel and air from said fuel tube "and primary air tube at an oblique angle to the direction pf flow'through said fuel and primary air tubes.

'An oil burner adapted to be supported at an end of a'combustion tube for burning oil in said tube including,

. a'main' housing having a cylindrical bore extending inwardly from one end and a secondary air chamber extending inwardly from the opposite end, said cylindrical boreand said secondary air chamber joining each other intermediate the ends of said main housing, said main housing also having a primary air inlet opening into said {cylindrical bore and a secondary air inlet opening into said secondary air chamber, a support member removably positioned in said cylindrical bore, said support member -having'axially spaced outer and inner end discs and connecting strut means extending between said end discs in off-center relation thereto, said inner end disc having an opening therein, a primary air tube supported by said innerend disc and extending inwardly through said secondary airchamber, the space between said inner and jloujter'end discs'being connected to the interior of said primary air'tube by said opening in said inner end disc, said outer end disc having an aperture extending there- ,through, and an oil tube extending through said aperture in said outer disc'and' supported by said support member, said oil tube extending inwardly through said opening in said inner end disc into said primary air tube, said primary air inlet in said main housing opening into the space between said end discs of said support member.

4. An oil burner adapted to be supported at an end of a combustion tube for burning oil in said tube including, a main housing having a cylindrical bore extending inwardly from one end and a secondary air chamber extending inwardly from the opposite end, said cylindrical bore and said secondary air chamber joining each other intermediate the ends of said main housing, said main housing also having a primary air inlet opening into said cylindrical bore and a secondary air inlet opening into said secondary air chamber, a support member removably positioned in said cylindrical bore, said support member having axially spaced outer and inner end discs and connecting strut means extending between said end discs in off-center relation thereto, said inner end disc having an opening therein, a primary air tube supported by said inner end disc and extending inwardly through said secondary air chamber, the space between said inner and outer end discs being connected to the interior of said primary air tube by said opening in said inner end disc, said outer end disc having an aperture extending therethrough, and an oiltube extending through said aperture in said outer disc and supported by said support member, said'oil tube extending inwardly through said opening in said inner end disc into said primary air tube, said primary air inlet in said main housing opening into the space between said end discs of said support member, and a tubular ignition chamber at the outer end of said oil tube and having a curved outer end portion adapted to discharge oil and air from said oil tube and said primary air tube at an oblique angle to the direction of flow through said oil and primary air tubes.

5. An oil burner adapted to be supported at an end of a combustion tube for burning oil in said tube including, a main housing having a cylindrical bore extending inwardly from one end and a secondary air chamber extending inwardly from the opposite end, said cylindrical bore and said secondary air chamber being co-axially arranged and joining each other intermediate the ends of said main housing, said main housing also having a primary air inlet opening into said cylindrical bore and a secondary air inlet opening into said secondary air chamber, a support member removably positioned in said cylindrical bore, said support member having axially spaced outer and inner end discs and connecting strut means extending between said end discs in ofi-center relation thereto, said inner end disc having a central opening therein, a primary air tube supported by said inner end disc and extending through said secondary air chamber, the space between said inner and outer end discs being connected to the interior of said primary air tube by said central opening in said inner end disc, said outer end disc having a central aperture extending therethrough, an oil tube supported by said outer end disc and extending through said central aperture therein, said oil tube further extending inwardly through said central opening in said inner end disc into said primary air tube, the inner ends of said primary air tube and said oil tube being disposed to form an oil spray nozzle, said primary air inlet in said main housing opening into the space between end discs of said support member whereby primary air is directed into said primary air tube, sealing means for maintaining gas tight seals between said end discs and the wall of said cylindrical bore, and means for securing said support member in said bore whereby, when said securing means is released, said support member, oil tube and primary air tube may be removed as a unit from said main housing.

6. An oil burner adapted to be supported at an end of a combustion tube for burning oil in said tube including,

.a mainhousing having a cylindrical bore extending inwardly from one end and a secondary air chamber'extending inwardly from the oppposite end, said cylindrical bore and said secondary air chamber being coeaxially arranged and joining each other intermediate the ends of said main housing, said main housing also having a primary air inlet opening into said cylindrical bore and a,

secondary air inlet opening into said secondary air chamber, a support member removably positioned in said cylindrical bore, said support member having axially spaced outer and inner discs and connecting strut means extending between said end discs in oflE-center relation thereto, said inner end disc having a central opening therein, a primary air tube supported by said inner end disc and extending through said secondary air chamber, the space between said inner and outer end discs being connected to the interior of said primary air tube by said central opening in said inner end discs, said outer end disc having a central aperture extending therethrough, an oil tube supported by said outer end disc and extending through said central aperture therein, said oil tube further extending inwardly through said central opening in said inner end disc into said primary air tube, the inner ends of said primary air tube and said oil tube being disposed to form an oil spray nozzle, a tubular ignition chamber member adjacent and surrounding said oil spray nozzle, the outer end portion of said ignition chamber member being curved and adapted to discharge air and oil at an oblique angle to the direction of flow through said oil and primary air tubes, said primary air inlet in said main housing opening into the space between said end discs of said support member whereby primary air is directed into said primary air tube, sealing means for maintaining gas tight seals between said end discs and the wall of said cylindrical bore, and means for securing said support member in said bore.

7. In a combustion tube having an inlet portion and a combustion portion disposed at an oblique angle to each other and connected by an elbow portion, a fuel burner removably supported at the end of said inlet portion, said burner having a fuel nozzle disposed adjacent the outer end of said elbow portion and an ignition chamber member adjacent and surrounding said nozzle, said ignition chamber member having a straight tubular portion spaced from and within said inlet portion of said combustion tube whereby air may pass through said inlet portion of said combustion tube around said straight,

tubular portion of said ignition chamber member, means for conducting air to said inlet portion of said combustion tube, and means for conducting air into said ignition chamber member, the outer end portion of said ignition chamber member being curved and adapted to conduct air and fuel through said elbow portion and discharge same axially into said combustion portion of said combustion tube.

8. In a combustion tube having an inlet portion and a combustion portion disposed at an oblique angle to each other and connected by an elbow portion, a fuel burner having a fuel nozzle disposed within said combustion tube adjacent the outer end of said'elbow portion and an ignition chamber member adjacent and surrounding said fuel nozzle, said ignition chamber member having a straight tubular port-ion spaced from and within said inlet portion of said combustion tube whereby air may pass through said inlet portion of said combustion tube around said straight tubular portion of said ignition chamber member, means for conducting air to saidinlet portion of said combustion tube, and means for conducting air into said ignition chamber member, the outer end portion of said ignition chamber member being curved on substantially the same radius as said elbow portion of said combustion tube and adapted to direct air and fuel substantially axially into said combustion portion of said combustion tube.

9. In a combustion tube having an inlet portion and a combustion portion disposed at an oblique angle to each otherand connected by an elbow portion, a fuel burner disposed within said inlet portion of said combustion tube adjacent the outer end of said elbow portion, said fuel burner including a fuel nozzle and an ignition chamber adjacent and surrounding said fuel nozzle, and means for conducting air into said ignition chamber member, the outer end portion of said ignition chamber being curved and being adapted to conduct air and fuel through said elbow portion and discharge same axially into said combustion portion of said combustion tube, the outer curved end portion of said ignition chamber being hingedly connected at its top to the adjacent portion thereof whereby withdrawal of said oil burner axially out of said inlet portion of said combustion tube is facilitated.

10. In a combustion tube having an inlet portion and a. combustion portion disposed at an oblique angle to each other and connected by an elbow portion, a fuel burner removably supported at the end of said inlet portion, said fuel burner having a fuel nozzle disposed within said combustion tube adjacent the outer end of said elbow portion and an ignition chamber member adjacent and surrounding said fuel nozzle, and means for conducting air into said ignition chamber member, the outer end portion of said ignition chamber member being curved on substantially the same radius as said elbow portion of said combustion tube and being adapted to direct air and fuel axially into said combustion portion of said tube, said outer curved end portion of said ignition chamber tube being hingedly connected at its top to the adjacent portion thereof.

11. In combination with a combustion tube having an inlet portion connected, to a substantially normally extending combustion portion by an elbow portion, an oil burner supported on and extending into said inlet portion of said combustion tube and having an oil nozzle adjacent the outer end of said elbow portion, a tubular ignition chamber member having a straight tubular portion adjacent and surrounding said oil nozzle and an elbow portion disposed in said elbow portion of said combustion tube, said straight tubular portion of said ignition chamber member being spaced from and within said inlet portion of said combustion tube whereby air may pass through said inlet portion of said combustion tube around said straight tubular portion of said ignition chamber member, means for conducting air to said inlet portion of said combustion tube, and means for conducting air into said ignition chamber member, said elbow portion of said ignition chamber member being adapted to discharge into and axially of said combustion portion of said combustion tube.

12. In combination with, a combustion tube having an inlet portion connected to a substantially normally extending combustion portion of an elbow portion, an oil burner supported on and extending into said inlet portion of said combustion tube and having an oil nozzle adjacent the outer end of said elbow portion, a tubular ignition chamber member having a portion adjacent and surrounding said oil nozzle and an elbow portion disposed in said elbow portion of said combustion tube elbow, and means for conducting air into said ignition chamber member, said elbow portion of said. ignition chamber member being adapted to discharge into and axially Of said combustion portion of said combustion tube and being hingedly connected at its top to said first named portion of said ignition chamber member.

, References Cited in the file of this patent UNITED STATES PATENTSv Grifiiths V t July 16, 1912 Tyrrell May 20, 1924 Parker et al. ...p... June 18, 1957 

